Telescoping atherectomy device

ABSTRACT

Telescoping, self-driving, and laterally-pushing atherectomy devices are provided, each having a flexible sheath, a cutter with helical flutes, and a drive assembly. The drive assembly can have a flexible driveshaft that is rotatably translational with the lumen of the flexible sheath, a positive displacement pump that begins pumping at the distal end of the drive shaft adjacent to the helical flutes at the proximal end of the cutter, and the flexible drive shaft can be longer than the flexible sheath to enable a reversible telescoping of the drive assembly from the lumen of the flexible sheath. The positive displacement pump can be a screw pump having a drive screw portion extending beyond the flexible sheath, exposed for contact with a vascular lumen for the self-driving. And, the devices can have a reversibly-expandable, lateral pushing member at the distal end of the flexible sheath for the lateral pushing.

CROSS REFERENCES TO RELATED APPLICATIONS

This is a continuation application of U.S. application Ser. No.17/518,294, filed Nov. 3, 2021, which claims priority to U.S.Provisional Application Nos. 63/126,847, filed Dec. 17, 2020, and63/197,970, filed Jun. 7, 2021, each of which is hereby incorporatedherein by reference in its entirety.

BACKGROUND Field of the Invention

The teachings herein are directed generally to medical devices andmethods, including devices and methods for performing atherectomies.

Description of the Related Art

An atherectomy is a minimally invasive procedure for removingatherosclerosis from blood vessels within the body and is an alternativeto angioplasty in the treatment of narrowing arteries. Commonapplications include peripheral arterial disease and coronary arterydisease. Unlike angioplasty and stents, which push plaque into thevessel wall, the atherectomy procedure cuts plaque away from the wall ofa blood vessel. While atherectomies are usually used to remove plaquefrom arteries, they can also be used in veins and vascular bypassgrafts, for example.

Atherectomies can offer improvements over balloon dilatation and stentplacement, which are considered traditional interventional surgicalmethods of treating atherosclerosis. In balloon dilatation, a collapsedballoon is inserted into a blood vessel and inflated to push plaqueagainst the vessel wall, and the stent can be placed to hold the plaqueas a scaffolding in order to try and maintain the integrity of the lumenof the vessel. However, such traditional treatments can stretch theartery and induce scar tissue formation, while the placement of a stentmay also cut arterial tissue and induce scar tissue formation. The scartissue formation can lead to restenosis of the artery. Moreover, thedilatation with the balloon can also rip the vessel wall. Becauseatherectomies enlarge the lumen by removing plaque rather thanstretching the vessel, risk of suffering vessel injuries, such asdissections that can lead to increased restenosis, is reduced.

Unfortunately, the art suffers performance limitations instate-of-the-art atherectomy devices. For example, current devices withrotating cutters cannot handle the variety of soft, fibrous and calcificplaque effectively, either not cutting all types of plaque or breakingup the plaque into large pieces that remain in the arterial bed asemboli that can clog blood vessels downstream. As plaque is a tissuemade of fat, cholesterol, calcium, fibrous connective tissue and othersubstances found in the body, it can be highly variable and classifiedmainly into four different types of tissue: calcified and hard, necroticand soft, fibrotic, and a combination thereof. Calcified plaque can behard as a bone; fatty plaque is typically soft; and fibrotic plaque istypically viscoelastic, stretchy yet firm, and thus difficult to cut.Some state-of-the-art devices have burrs that can grind-away hard plaquebut can't cut soft or viscoelastic plaque. Worse yet, they can loosendebris that can become dangerous emboli. Some state-of-the-art deviceshave a sharp cutter that can be deflected against one side of the vesselto do eccentric cutting, which is desirable, but the amount ofdeflection can't be effectively controlled. And, some state-of-the-artdevices have a “nose cone” that prevents the cutter from cutting throughlesion that doesn't allow enough progression of the device to reach thecutter blades.

Most importantly, however, is that patients having “tight” or “tough”lesions are currently unable to receive treatments with balloons,stents, or atherectomy devices. Such lesions are occlusions that leaveonly a very small luminal opening, or no opening, making itdifficult-to-impossible to achieve passage of a guidewire, much lesspassage of a balloon or stent on the guidewire. For example, a luminalopening that is only 0.5 mm may allow passage of a guidewire, perhaps,but the smallest stents may be 1.0 mm, and the smallest balloon may be0.75 mm, neither of which can pass through a tough, small lesion for thetreatment. And, as noted above, current atherectomy devices have adifficult time cutting away the plaque, even if the guidewire might beable to pass through the luminal opening. In situations having a totalocclusion, the problem is exacerbated.

As such, one of skill will appreciate an atherectomy device that (i) caneffectively cut and remove the 4 different types of plaque tissue,namely calcified and hard, necrotic and soft, fibrotic, and acombination thereof; (ii) can render a concentric vessel lumen withminimal plaque burden; (iii) can safely self-collect and remove plaqueparticles to avoid release of emboli; and, (iv) can effectively treat ablood vessel with a reduced risk of suffering vessel injuries that canlead to increased restenosis. In addition, the skilled artisan willcertainly appreciate having an atherectomy device that (v) can handlethese tight or tough lesions.

SUMMARY

Atherectomy devices, and methods of using them are provided, namelydevices and methods that (i) can effectively cut and remove the 4different types of plaque tissue, namely calcified and hard, necroticand soft, fibrotic, and a combination thereof; (ii) can render aconcentric vessel lumen with minimal plaque burden; (iii) can safelyself-collect and remove plaque particles to avoid release of emboli;(iv) can effectively treat a blood vessel with a reduced risk ofsuffering vessel injuries that can lead to increased restenosis; and,importantly, (v) can also handle tight or tough lesions having little tono luminal opening in the lesion. The atherectomy devices taught hereincan be telescoping, self-driving, lateral pushing, or a combinationthereof.

In some embodiments, the atherectomy device is a telescoping atherectomydevice. In these embodiments, the device can have a distal end, aproximal end, a long axis, and a guidewire lumen passing through thedevice in the direction of the long axis. The device can include aflexible sheath having an outer diameter and a sheath lumen; a cutterhaving a proximal end, a distal end, and a body with a plurality ofhelical flutes, a point at the distal end having a plurality of cuttinglips, a cutter lumen, and a cleared diameter; and, a drive assembly. Thedrive assembly can have a flexible driveshaft including an axis, aproximal end, a distal end, an outer surface, and a driveshaft lumen,the distal end of the flexible drive shaft having a fixed connectionwith the cutter, wherein the flexible drive shaft is rotatablytranslational with the lumen of the flexible sheath. The drive assemblycan also have a positive displacement pump that begins pumping at thedistal end of the drive shaft and adjacent to the helical flutes at theproximal end of the cutter. And, in these embodiments, the cleareddiameter of the cutter can be greater than the outer diameter of theflexible drive shaft; the flexible drive shaft can be longer than theflexible sheath to enable a reversible telescoping of the drive assemblyfrom the lumen of the flexible sheath at the distal end of the flexiblesheath; and, the guidewire lumen can include the cutter lumen and thedriveshaft lumen.

In some embodiments, the cleared diameter of the cutter can be greaterthan the outer diameter of the flexible sheath. And, in someembodiments, the positive displacement pump can be a screw pump attachedto the outer surface of the drive shaft, the distal end of the screwpump being adjacent to the helical flutes at the proximal end of thecutter.

In some embodiments, the telescoping atherectomy device can beself-driving. For example, the screw pump can extend beyond the flexiblesheath and can be exposed for contact with a vascular lumen during useof the atherectomy device within the vascular lumen. In someembodiments, the screw pump can be a right hand screw when the cutter isrotated in the right-hand direction; and, in some embodiments, the screwpump can be a left hand screw when the cutter is rotated in theleft-hand direction.

In some embodiments, the telescoping atherectomy device can furthercomprise a reversibly-expandable, lateral pushing member at the distalend of the flexible sheath. In some embodiments, the telescopingatherectomy device can further comprise a reversibly-expandable, lateralpushing member at the distal end of the flexible sheath, the lateralpushing member having a proximal end, a distal end, a collapsed state,and an expanded state, the proximal end having an operable connectionwith the flexible sheath, and the distal end having an operableconnection with the cutter. The operable connection with the flexiblesheath and the operable connection with the cutter can each beconfigured to receive an axial force (i) applied along the axis of theflexible drive shaft from the cutter to the flexible sheath and (ii)transferred through the lateral pushing member during the collapse andthe expansion of the lateral pushing member with the reversibletelescoping of the flexible drive shaft from the flexible sheath.Moreover, the operable connection with the cutter can be configured as arotatably translatable connection to facilitate a rotation of the cutterand the flexible drive shaft without rotating the lateral pushing memberduring operation of the atherectomy device.

In some embodiments, the atherectomy device is a self-drivingatherectomy device. In these embodiments, the device can have a distalend, a proximal end, a long axis, and a guidewire lumen passing throughthe device in the direction of the long axis. The device can include aflexible sheath having an outer diameter and a sheath lumen; a cutterhaving a proximal end, a distal end, and a body with a plurality ofhelical flutes, a point at the distal end having a plurality of cuttinglips, a cutter lumen, and a cleared diameter; and, a drive assembly. Thedrive assembly can have a flexible driveshaft including an axis, aproximal end, a distal end, an outer surface, and a driveshaft lumen,the distal end of the flexible drive shaft having a fixed connectionwith the cutter, wherein the flexible drive shaft is rotatablytranslational with the lumen of the flexible sheath. The drive assemblycan also have a screw pump attached to the outer surface of the driveshaft and adjacent to the helical flutes at the proximal end of thecutter, the screw pump including a drive screw portion. In someembodiments, the drive screw portion can extend beyond the flexiblesheath and can be exposed for contact with a vascular lumen during useof the atherectomy device within the vascular lumen. In someembodiments, the drive screw portion can be a right hand screw when thecutter is rotated in the right-hand direction; and, in some embodiments,the drive screw portion can be a left hand screw when the cutter isrotated in the left-hand direction. And, in these embodiments, thecleared diameter of the cutter can be greater than the outer diameter ofthe flexible drive shaft; and, the guidewire lumen can include thecutter lumen and the driveshaft lumen.

In some embodiments, the cleared diameter of the cutter of theself-driving atherectomy device can be greater than the outer diameterof the flexible sheath. And, in some embodiments, the drive screwportion can be the distal portion of the screw pump.

In some embodiments, the flexible drive shaft of the self-drivingatherectomy device can be longer than the flexible sheath to enable areversible telescoping of the drive assembly from the lumen of theflexible sheath at the distal end of the flexible sheath.

In some embodiments, the self-driving atherectomy device can furthercomprise a reversibly-expandable, lateral pushing member at the distalend of the flexible sheath. In some embodiments, the lateral pushingmember can have a proximal end, a distal end, a collapsed state, and anexpanded state, the proximal end having an operable connection with theflexible sheath, and the distal end having an operable connection withthe cutter. The operable connection with the flexible sheath and theoperable connection with the cutter can each be configured to receive anaxial force (i) applied along the axis of the flexible drive shaft fromthe cutter to the flexible sheath and (ii) transferred through thelateral pushing member during the collapse and the expansion of thelateral pushing member with the reversible telescoping of the flexibledrive shaft from the flexible sheath. Moreover, in some embodiments, theoperable connection with the cutter can be configured as a rotatablytranslatable connection to facilitate a rotation of the cutter and theflexible drive shaft without rotating the lateral pushing member duringoperation of the atherectomy device.

In some embodiments, the atherectomy device is a lateral pushingatherectomy device. In these embodiments, the device can have a distalend, a proximal end, a long axis, and a guidewire lumen passing throughthe device in the direction of the long axis. The device can include aflexible sheath having an outer diameter and a sheath lumen. a cutterhaving a proximal end, a distal end, and a body with a plurality ofhelical flutes, a point at the distal end having a plurality of cuttinglips, a cutter lumen, and a cleared diameter; and, a drive assembly. Thedrive assembly can have a flexible driveshaft including an axis, aproximal end, a distal end, an outer surface, and a driveshaft lumen,the distal end of the flexible drive shaft having a fixed connectionwith the cutter, wherein the flexible drive shaft is rotatablytranslational with the lumen of the flexible sheath. The drive assemblycan also have a positive displacement pump that begins pumping at thedistal end of the drive shaft and adjacent to the helical flutes at theproximal end of the cutter. And, the lateral pushing atherectomy devicecan also have a reversibly-expandable, lateral pushing member at thedistal end of the flexible sheath. In these embodiments, the cleareddiameter of the cutter can be greater than the outer diameter of theflexible drive shaft; and, the guidewire lumen can include the cutterlumen and the driveshaft lumen.

In some embodiments, the cleared diameter of the cutter can be greaterthan the outer diameter of the flexible sheath.

In some embodiments, the lateral pushing member can have a proximal end,a distal end, a collapsed state, and an expanded state, the proximal endhaving an operable connection with the flexible sheath, and the distalend having an operable connection with the cutter. In some embodiments,the operable connection with the flexible sheath and the operableconnection with the cutter can each be configured to receive an axialforce (i) applied along the axis of the flexible drive shaft from thecutter to the flexible sheath and (ii) transferred through the lateralpushing member during the collapse and the expansion of the lateralpushing member with the reversible telescoping of the flexible driveshaft from the flexible sheath. And, in some embodiments, the operableconnection with the cutter can be configured as a rotatably translatableconnection to facilitate a rotation of the cutter and the flexible driveshaft without rotating the lateral pushing member during operation ofthe atherectomy device.

In some embodiments, the flexible drive shaft of the laterally pushingatherectomy device can be longer than the flexible sheath to enable areversible telescoping of the drive assembly from the lumen of theflexible sheath at the distal end of the flexible sheath. And, in someembodiments, the laterally pushing atherectomy device can comprise adrive screw attached to the outer surface of the distal end of the driveshaft and adjacent to the screw pump at the distal end of the screwpump. The drive screw can extend beyond the flexible sheath and can beexposed for contact with a vascular lumen during use of the atherectomydevice within the vascular lumen. In some embodiments, the drive screwcan be a right hand screw when the cutter is rotated in the right-handdirection; and, in some embodiments, the drive screw can be a left handscrew when the cutter is rotated in the left-hand direction.

Systems are also provided. In some embodiments, any of the atherectomydevices taught herein can be a system comprising the atherectomy deviceand a guidewire.

Methods of performing an atherectomy in a subject using any of theatherectomy devices taught herein are provided. In some embodiments, themethods can include creating a point of entry in a vascular lumen of thesubject; inserting the atherectomy device into the vascular lumen;telescoping the flexible drive shaft; cutting a plaque from the vascularlumen with the cutter of the atherectomy device; discharging the cutplaque from the vascular lumen with the positive displacement pump; and,removing the atherectomy device from the vascular lumen of the subject.

In some embodiments, the methods can include creating a point of entryin a vascular lumen of the subject; inserting the atherectomy deviceinto the vascular lumen; driving the atherectomy device through thevascular lumen with the exposed drive screw; cutting a plaque from thevascular lumen with the cutter of the atherectomy device; dischargingthe cut plaque from the vascular lumen with the positive displacementpump; and, removing the atherectomy device from the vascular lumen ofthe subject.

Likewise, in some embodiments, the methods can include creating a pointof entry in a vascular lumen of the subject; inserting the atherectomydevice into the vascular lumen; pushing the distal portion of theatherectomy device laterally in the vascular lumen, the pushingincluding expanding the lateral pushing member; cutting a plaque fromthe vascular lumen with the cutter of the atherectomy device;discharging the cut plaque from the vascular lumen with the positivedisplacement pump; and, removing the atherectomy device from thevascular lumen of the subject.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1C illustrate the anatomy of an artery, intimal plaque, and amethod of plaque removal, according to some embodiments.

FIGS. 2A and 2B illustrate a telescoping atherectomy device, accordingto some embodiments.

FIG. 3 illustrates a telescoping atherectomy device that can beself-driving, according to some embodiments.

FIGS. 4A-4D illustrate a telescoping atherectomy device that can furthercomprise a reversibly-expandable, lateral pushing member at the distalend of the flexible sheath, wherein the expansion of the lateral pushingmember induces a curve, according to some embodiments.

FIGS. 5A-5D illustrate a compressible sleeve that can be used toincrease the torsional stiffness of the lateral pushing member, whereinthe expansion of the lateral pushing member induces a curve, accordingto some embodiments.

FIGS. 6A and 6B illustrate other cutters that may be used, according tosome embodiments.

DETAILED DESCRIPTION

Atherectomy devices, and methods of using them are provided, namelydevices and methods that (i) can effectively cut and remove the 4different types of plaque tissue, namely calcified and hard, necroticand soft, fibrotic, and a combination thereof, including fibrocalcifictissue; (ii) can render a concentric vessel lumen with minimal plaqueburden; (iii) can safely self-collect and remove plaque particles toavoid release of emboli; (iv) can effectively treat a blood vessel witha reduced risk of suffering vessel injuries that can lead to increasedrestenosis. And, importantly, one of skill will certainly appreciate anatherectomy device that, surprisingly, (v) can also handle tight ortough lesions having little to no luminal opening in the lesion. Theatherectomy devices taught herein can be telescoping, self-driving,lateral pushing, or a combination thereof. The devices provided hereincan, for example, render a concentric lumen with minimal plaque burden(<30% vessel diameter) while avoiding damage to vessel wall andminimizing embolization.

FIGS. 1A-1C illustrate the anatomy of an artery, intimal plaque, and amethod of plaque removal, according to some embodiments. FIG. 1Aillustrates the anatomy of an artery 100. The anatomy of arteries canvary by size of the artery, but arteries share common characteristics.They transport oxygenated blood from the heart and to smallerarterioles. The outermost layer is the tunica externa, or tunicaadventitia, and is composed of collagen fibers. The largest arteries,like the aorta, also have vasa vasorum, or small blood vessels thatsupply oxygen to the large blood vessels. The next layer in is thetunica media, which is a combination of smooth muscle, collagen fiber,and is elastic. The next layer is the tunica interna or intima, which isalso elastic with endothelial cells supported by a layer of collagen.These layers all surround the vascular lumen, which is the wall uponwhich the undesirable plaque forms and is removed with the atherectomydevices taught herein. FIG. 1B illustrates plaque 110 that has depositedon the wall of the arterial lumen 105.

Those of skill understand that guidewires can be used to locate adiseased region, or target region, in a blood vessel. Also, a guidewirecan be used to direct the atherectomy devices taught herein, namely thecutter, over the target region. In some embodiments, the guidewire lumencan include the cutter lumen and the driveshaft lumen. In someembodiments, the guidewire lumen diameter can range in size from 0.01 to0.20 inches, from 0.01 to 0.18 inches, from 0.01 to 0.15 inches, from0.01 to 0.10 inches, or any range therein in some embodiments. In someembodiments, the guidewire lumen diameter can range from 0.01 to 0.14inches. In some embodiments, the guidewire lumen diameter is 0.01 inches(0.254 mm), 0.02 inches (0.508 mm), 0.04 inches (1.016 mm), 0.06 inches(1.524 mm), 0.08 inches (2.032 mm), 0.10 inches (2.540 mm), 0.12 inches(3.048 mm), 0.14 inches (3.556 mm), 0.16 inches (4.064 mm), 0.18 inches(4.572 mm), 0.20 inches (5.080 mm), or any diameter therein inincrements of 0.01 inches (0,254 mm).

FIG. 10 is a flowchart of an atherectomy method 150 that can be usedwith the atherectomy devices taught herein to remove plaque from anartery. A guidewire is advanced 174 through a guiding catheter andacross a blockage in the blood vessel created by the arterial plaque inthe target area. Once the guidewire is in place across the blockage, anatherectomy device is advanced 176 across the blockage on the guidewire.The atherectomy device is then in proper position to cut and remove 178plaque in the target area to treat the artery and remove the blockage.At this time, a stent can optionally be inserted 180 in the target areato help maintain the newly created opening in the lumen. To complete theprocedure, the atherectomy device and guidewire are removed 182 from thepatient.

Generally speaking the atherectomy devices can include a cutter, orcutting head, that is attached to a drive shaft that rotates the cutter,and the drive shaft rotates within a sheath. The sheath can beinterchangeably called a “flexible tube”, in some embodiments; and, thedrive shaft can be referred to as a “torque shaft”, in some embodiments.In some embodiments, the cutter can be designed to telescope from thesheath and, in some embodiments, reversibly telescope from the sheath.In some embodiments, the cutter can extend out, or telescope, from thesheath as far as desired. For example, the cutter can telescope from,perhaps, 10 mm to 500 mm from the end of the sheath on the drive shaftin some embodiments. The telescoping allows the cutter and the distalportion of the drive shaft to advance ahead of the sheath during whichan improved engagement between the cutter and the plaque tissue can beachieved. In addition, leaving the sheath static while moving the cutterin advance of the sheath allows the sheath to resist drill through. Insome methods, the telescoping can be the sole step in the removal ofplaque from a vessel. In some embodiments, the telescoping can providean initial cutting path to facilitate a subsequent and moretarget-specific eccentric cutting.

FIGS. 2A and 2B illustrate a telescoping atherectomy device, accordingto some embodiments. In these embodiments, the atherectomy device 200can have a distal portion with a distal end 202, a proximal portion witha proximal end (not shown), a long axis having a central axis 205, and aguidewire lumen passing through the device in the direction of thecentral axis 205 for a guidewire 210. For perspective, the generaldirection of orientation from proximal to distal, and distal toproximal, are illustrated in FIG. 2A. The device can include a flexiblesheath 215 having a proximal portion with a proximal end (not shown), adistal portion with a distal end 217, an outer diameter 219, and asheath lumen 221; a drive shaft 250; a cutter 230 having a proximalportion with a proximal end 232, a distal portion with a distal end 234,and a body 236 with a plurality of helical flutes 238 between the cutterblades 240. The distal end 234 can have a plurality of cutting lips onthe cutter blades 240, and, in some embodiments, the distal end 234 canhave a point. The cutter can have a cutter lumen 242, and a cleareddiameter 260.

The drive shaft can be made using any construct known to one of skillthat meets the axial stiffness, flexural stiffness, torsional stiffness,and the like. In some embodiments, for example, the drive shaft includesa distal end and a proximal end, in which the distal end connects to oraffixed to the cutter, and the proximal end connected to a rotatableelement such as a gear attached to a motor or attached to motor itself.The drive shaft may be, in turn, driven by the motor in the handle. Thedrive shaft can be made using a metal braid and/or one or more metalcoils, and one or more portions of the drive shaft embedded in apolymer. In some embodiments, the polymer can include PEBAX,polyurethane, polyethylene, fluoropolymers, parylene, polyimide, PEEK,PET, or a combination thereof. In some variations, the drive shaft caninclude a rigid material such as plastic, rendered flexible byincorporation of a spiral relief or groove. During a procedure, themotor drives the gear to rotate drive shaft and cutter to cut the tissuein a target lesion.

One of skill will appreciate that the “cleared diameter” of a vessel canbe used to describe the diameter of the lumen of the blood vessel afterpassage of the cutter portion of the atherectomy device through thelumen of the vessel. Since the vessel is often elastic, the cleareddiameter 260 of the lumen of a blood vessel may or may not be equal tothe diameter of the cutter 230. The cleared diameter 260 of the cutter230 can be greater than the outer diameter of the flexible drive shaft250. In some embodiments, the cleared diameter of the cutter can begreater than the outer diameter of the flexible sheath. And, in someembodiments, the cleared diameter 260 of the lumen is less than thediameter of the body of the cutter 230.

Table 1 lists example arterial lumen diameters in mm, beginning at theaorta and descending down a human leg, for example. Peripheral vasculardisease in the legs is an example of a condition that can be treatedusing the atherectomy devices taught herein.

TABLE 1 Examples of arterial lumen diameters in mm. Superior AnteriorTibio- Posterior femoral Popliteal tibial peroneal tibial Peroneal Aortaartery artery artery trunk arteries arteries (mm) (mm) (mm) (mm) (mm)(mm) (mm) 17-35 5-7 3.5-4.5 3.0 2.5 2.0 2.0

the superior femoral artery, located about mid-femur, generally has adiameter of about 5 to 7 mm, or about 0.2 to 0.25 inch. As the arterydescends below the knee, the popliteal artery generally has a diameterof about 4 to 4.5 mm (0.157 inch to 0.177 inch), and then reduces toabout 3.5 mm (0.137 inch) as you move in the direct of the subject'sfoot. The popliteal artery branches again into the anterior tibialartery and the tibioperoneal trunk, reducing further in diameter toabout 3.0 mm and then about 2.5 mm or about 0.118 inch to 0.098 inch.The tibioperoneal trunk further subdivides into the posterior tibial andperoneal arteries, further reducing in diameter to about 2.0 mm (0.078inch). Generally speaking, the diameters of the peripheral arteries ofthe leg can vary, typically, from about 2 mm to about 7 mm. Any bloodvessel can contain plaque and be a prospective target area for theatherectomy devices taught herein. For example, coronary arteries areabout 3 mm in size, varies from 2.5-4.5 in diameter, and coronaryarteries are prospective target areas for the atherectomy devices taughtherein.

Although it seems reasonable to simply increase the diameter of thecutter for larger blood vessels, the skilled artisan will realize thatthe diameter of the cutter can also be limited by physical complicationsof the patient's anatomy. For example, there can be complications thatoccur during surgery due to bleeding at the arterial puncture access,tortuous vessels, vessel size variations, and the like. The diameter ofthe cutter can range from about 0.70 mm to about 2.20 mm in someembodiments, 1.00 mm to 2.20 mm in some embodiments, 1.20 mm to 2.20 mmin some embodiments, 1.40 mm to 2.20 mm in some embodiments, 1.50 to2.20 mm in some embodiments, or any range therein in increments of 0.10mm. In some embodiments, the diameter of the cutter can be about 0.90mm, 1.00 mm, 1.10 mm, 1.20 mm, 1.30 mm, 1.40 mm, 1.50 mm, 1.60 mm, 1.70mm 1.80 mm, 1.90 mm, 2.00 mm, 2.10 mm, 2.20 mm, 2.30 mm, or any diametertherein, or range therein, in increments of 0.05 mm. This issignificant, as blood vessel lumen diameters can be very small or quitelarge, and vessels having diameters of 1.00 mm are quite tight forcutters, and vessels having diameters over about 2.30 mm are becominglarger than a cutter can be made, in some embodiments. The skilledartisan will recognize that eccentric cutting allows for cutting alarger region than the diameter of the cutter assembly without adding orexchanging the cutter for other larger tools for removal. The cutter canbe biased off-center within the larger blood vessels to clear a lumenthat is larger than the diameter of the cutter.

The skilled artisan will also realize that the length of the cutter hasto be limited to have the maneuverability needed. One of skill willrealize that the size of the cutter can be any size known to be suitablein the art for the particular treatment. In some embodiments, the lengthof the cutter can range from about 0.50 mm to about 3.00 mm, from about0.60 mm to about 2.80 mm, from about 0.80 mm to about 2.60 mm, fromabout 1.00 mm to about 2.40 mm, from about 1.00 mm to about 2.20 mm,from about 1.00 mm to about 2.00 mm, from about 1.20 mm to about 1.80mm, or any range therein in increments of 0.10 mm.

The atherectomy device 200 further includes a drive assembly to drivethe cutter 230. The drive assembly can have a flexible driveshaft 250including a long axis having a central axis that can be coincident withthe central axis 205 of the atherectomy device 200. The flexibledriveshaft 250 can further have a proximal portion with a proximal end(not shown), a distal portion with a distal end 252, an outer surface254, and a driveshaft lumen 256, the distal end 252 of the flexibledrive shaft 250 having a fixed connection with the cutter 230. Theflexible drive shaft 250 can be rotatably translational with the lumen221 of the flexible sheath 215. The drive shaft 250 can extend to reacha driving engine located outside the subject receiving the atherectomy,the driving engine powered by an electric engine, in some embodiments,or powered by an air compressor in some embodiments, and the drive shaft250 can be operably connected to a handle (not shown) at the proximalend of the atherectomy device for control by a user. The drive assemblycan also have a positive displacement pump that pumps from the distalportion of the drive shaft 250 and adjacent to the helical flutes 238 atthe proximal end of the cutter 230. In some embodiments, the positivedisplacement pump extends from the distal portion of the drive shaft 250to the proximal portion of the driveshaft 250 to pump cut pieces ofarterial plaque from a blood vessel.

One of skill will appreciate that the subject is a patient that isreceiving the atherectomy. The term “subject” and “patient” can be usedinterchangeably and refer to an animal such as a mammal including, butnot limited to, non-primates such as, for example, a cow, pig, horse,cat, dog, rabbit, rat and mouse; and primates such as, for example, amonkey or a human. The subject can also be a cadaver, in someembodiments, or a portion of a cadaver.

The flexible drive shaft 250 can be longer than the flexible sheath 215to enable a reversible telescoping 270 of the drive assembly from thelumen 221 of the flexible sheath 215 at the distal end 252 of theflexible sheath 215. The guidewire lumen can include the cutter lumen242 and the driveshaft lumen 256. Although the flexural stiffness of thedrive shaft 250 remains the same between the collapsed and expandedstates of the device, the flexural movement 290 increases upon thetelescoping 270 of the drive shaft from the flexible sheath 215. Assuch, the amount of flexural movement 290 available is greater in FIG.2A than in FIG. 2B, and the ease of flexural movement 290 is greater inFIG. 2A than in FIG. 2B due to the length of the drive shaft that hasbeen telescoped in FIG. 2A as opposed to the length of the drive shaftexposed in FIG. 2B. We found that, as the amount and ease of flexuralmovement 290 increases due to the telescoping 270, the ease at which thecutter 230 can move through an artery increases.

In some embodiments, the cutter can be operably attached to the driveshaft using a friction fitting, so that the drive shaft is allowed slipon the base of the cutter when engaged with plaque and meeting a maximumtorque limit. And, in some embodiments, the positive displacement pumpcan be a screw pump 280, also referred to as an Archimedes screw in someembodiments. The positive displacement pump can be attached to the outersurface 254 of the drive shaft 250, the distal end of the screw pumpbeing adjacent to the helical flutes 238 at the proximal end 232 of thecutter 230 to transport pieces of cut plaque from the cutter in a distalto proximal direction to the proximal end of the atherectomy device forremoval of the cut plaque from the subject.

FIG. 3 illustrates a telescoping atherectomy device that can beself-driving, according to some embodiments. The atherectomy device 300can have a screw pump 380 in operable contact with a cutter 330, forexample. The screw pump 380 can extend beyond the flexible sheath 315and can be exposed for contact with a vascular lumen wall (not shown),often perhaps contact with remaining plaque on the lumen wall, duringuse of the atherectomy device within the vascular lumen. In someembodiments, the screw pump 380 can be a right hand screw (as shown)when the cutter 330 is rotated in the right-hand direction 390; and, insome embodiments, the screw pump 380 can be a left hand screw (oppositeas shown) when the cutter 330 is rotated in the left-hand direction(opposite direction to 390). As such, a right-handed cutter can have aright-handed screw pump, and a left-handed cutter can have a left-handedscrew pump, to enable the screw pump to assist in driving theatherectomy device 300 through the vascular lumen along the guidewire310 during the cutting of the vascular plaque in the vascular lumen. Oneof skill will understand that a self-driving device can offersubstantial value in that it can assist by reducing the forces neededfrom a surgeon, for example, during operation of the device. Theself-driving can be all or partial, meaning that that the device canremove the need for the surgeon to push the device during the procedure,in some embodiments. And, in some embodiments, it eases the pressurerequired from the surgeon during the procedure. Those skilled in the artof atherectomy procedures will understand that pushing can cause thedevice to buckle, break, or jam; and/or, the patient can suffercomplications through a perforation of a vessel receiving the treatment,as well as a perforation of a tissue surrounding the vessel receivingthe treatment.

The self-driving feature of the atherectomy devices taught herein canreduce the pressure required from a surgeon performing the procedure. Insome embodiments, the pressure required from the surgeon performing theatherectomy can be reduced by 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%,60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, or any amountor range therein in increments of 1%. In some embodiments, the pressurerequired from the surgeon performing the atherectomy can be reduced inan amount ranging from about 25% to about 100%, from about 30% to about100%, from about 35% to about 100%, from about 40% to about 100%, fromabout 45% to about 100%, from about 50% to about 100%, from about 60% toabout 100%, from about 65% to about 100%, from about 70% to about 100%,from about 75% to about 100%, from about 80% to about 100%, from about85% to about 100%, from about 90% to about 100%, from about 95% to about100%, or any range therein in increments of 1%. Likewise, in someembodiments, the pressure required from the surgeon performing theatherectomy can be reduced in an amount ranging from about 25% to about95%, from about 30% to about 90%, from about 35% to about 85%, fromabout 40% to about 80%, from about 45% to about 75%, from about 50% toabout 70%, from about 60% to about 100%, from about 65% to about 100%,from about 70% to about 100%, from about 75% to about 100%, from about80% to about 100%, from about 85% to about 100%, from about 90% to about100%, from about 95% to about 100%, or any range therein in incrementsof 1%. Likewise, in some embodiments, the pressure required from thesurgeon performing the atherectomy can be reduced in an amount rangingfrom about 25% to about 50%, from about 50% to about 100%, or any rangetherein in increments of 1%. Likewise, in some embodiments, the pressurerequired from the surgeon performing the atherectomy can be reduced byat least 20%, at least 30%, at least 40%, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, or at least any range therein inincrements of at 1%.

In some embodiments, a surgeon may need to apply a negative pressure,for example holding or pulling and not pushing, at times to aid controlin the cutting of a lesion. It should be appreciated that the negativepressure can be a negative 1%, 5%, 10%, 15%, 20%, or 25%, or any amounttherein in increments of 1%, in some embodiments. Such a negativepressure can result in slowing the forward movement of the cutting,stopping the cutting, or moving the cutting in a direction that opposesthe self-driving direction of the cutter.

Those of skill in the art will appreciate that the atherectomy deviceswill offer a needed versatility and maneuverability in the art fortortuous blood vessels. When plaque is located in tortuous vessels oroccluded eccentric to the passage of the vessel, eccentric cutting ofthe tissues can be useful to maneuver the cutting head to remove plaque.There have been atherectomy devices that offer a mechanism in the devicethat can create a curvature in the distal end of the device by pulling a“tendon” that pulls the end laterally. These devices suffer in that theycreate a “snapback” or “whip” motion of the device due to an imbalanceof stresses being placed along the long axis of the atherectomy device.The devices provided herein provide eccentric cutting without the“snapback” or “whip” created by these earlier known mechanisms.

FIGS. 4A-4D illustrate a telescoping atherectomy device that can furthercomprise a reversibly-expandable, lateral pushing member at the distalend of the flexible sheath, wherein the expansion of the lateral pushingmember induces a curve, according to some embodiments. As shown in FIG.4A, the telescoping atherectomy device 400 can further comprise areversibly-expandable, lateral pushing member 444 at the distal end ofthe flexible sheath 415, the pushing member 444 creating a lateralprotrusion relative to the central axis of the atherectomy device. Thelateral pushing member 444 can have a proximal portion with a proximalend, a distal portion with a distal end, and a reversibly-expandableportion having a collapsed state (as shown in FIG. 4A) and an expandedstate (as shown in FIGS. 4B and 4C). The protrusion can be rotatedrelative to the lesion in any amount, from 1-360 degrees, or any rangetherein, for example, to reach any target area inside of a blood vessel.

The lateral pushing member can be made of any material known to besuitable by those of skill. For example, the lateral pushing member canbe made of a flexible metal, a flexible metal that is biocompatible,such as titanium alloy such as Nickel Titanium. In some embodiments, thelateral pushing member can be made of a polymer such as PEEK, Polyimidor Nylon. The length of the trusses, or ribbon, can be designed toprovide any desired protuberance. For example, the length of the trussesmay vary from 1 mm-100 mm in some embodiments, 10 mm-30 mm in someembodiments, 10 mm to 40 mm in some embodiments, 10 mm to 50 mm in someembodiments, 20 mm to 60 mm in some embodiments, 20 mm to 80 mm in someembodiments, or any range therein. In some embodiments, the length ofthe trusses can be 1 mm, 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16mm, 18 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 100 mm, orany length therein in increments of 1 mm.

The reversibly-expandable portion has trusses 488 that expand andcollapse the reversibly-expandable lateral pushing member 444 throughthe application of axial forces on the lateral pushing member 444. Thetrusses can be referred to as “ribbons”, in some embodiments. Theproximal end of the lateral pushing member 444 has an operableconnection with the flexible sheath 415, and the distal end of thelateral pushing member 444 has an operable connection with the cutter430. The operable connection with the flexible sheath 415 and theoperable connection with the cutter 430 can each be configured toreceive an axial force (i) applied along the axis of the flexible driveshaft 450 from the cutter 430 to the flexible sheath 415 and (ii)transferred through the lateral pushing member 444 to expand the lateralpushing member 444 when applying a distal to proximal axial force, andthe collapse the lateral pushing member 444 when applying a proximal todistal axial force, the axial forces applied in the desired directionwith the reversible telescoping action of the flexible drive shaft 450within the flexible sheath 415. The lateral pushing member 444 has aneffective radius upon collapse 445 c and upon expansion 445 e.

In some embodiments, proximal-to-distal and distal-to-proximal forcesare received by the lateral pushing member 444 at a proximal collar 455on the proximal portion of the lateral pushing member 444 and at adistal collar 466 on the distal portion of the lateral pushing member444. Moreover, the operable connection between the lateral pushingmember 444 and the cutter 430 can be configured as a rotatablytranslatable connection to facilitate a rotation of the cutter 430 andthe flexible drive shaft 450 without rotating, or undesirably torquing,the distal end of the lateral pushing member 444 during operation of theatherectomy device 400.

The axial forces can be applied using any structure, a centralizedmember, for example a tendon, that applies the force along the centralaxis of the drive shaft to avoid inducing a load on the atherectomydevice resulting in release of the snapback or whip forces along thelong axis of the device. In some embodiments, the structure providingthe axial force can be the drive shaft that is already located centralto the device, for example, concentric within the sheath. As such, insome embodiments, the method of expanding the lateral pushing memberincludes applying a distal-to-proximal force to the distal portion ofthe lateral pushing member, the force applied along the central axis ofthe atherectomy device, the central axis of the drive shaft, or thecentral axis of the sheath.

The contact of the lateral pushing member 444 on the vessel walllaterally pushes the cutter 430 away from the central axis of the vessellumen opposite direction of expansion of the trusses 488. The magnitudeof the diversion of the cutter 430 is adjustable and controllable.

As shown in FIG. 4B, the expansion of the trusses 488 on the lateralpushing member 444 causes the cutter 430 of the atherectomy device 400to deflect toward the vascular lumen wall 499 that is opposite thevascular lumen wall 499 receiving force from the expansion of thetrusses 488.

One or more expandable trusses can be used. In some embodiments, thereis a single truss. In some embodiments, there are 2 trusses. In someembodiments, there are 3 trusses. In some embodiments, there are 4trusses. In some embodiments, there are at least 1, 2, 3, 4, 5, 6, 7, 8,9, or 10 trusses. The trusses can be pre-shaped to create a biased curveor angle to protrude outwardly from the central axis of the device. Thatis, in some embodiments, the trusses have a shape memory that allows thetrusses to remain in the collapsed state, and the expanded state isobtained by applying a force to the trusses, for example, by pulling onthe central tendon, or drive shaft. In some embodiments, the trusseshave a shape memory that allows the trusses to remain in the expandedstate, and the collapsed state is maintained by holding the trusses inthe collapsed state, and the expanded state is obtained by releasingthat holding force and allowing the shape memory to return to thetrusses. The trusses can be any shape and, in some embodiments, can be asingle truss or a plurality of trusses. In some embodiments, the trussescan for a basket shape. In some embodiments, a balloon can be inflatedto bias the cutter, rather than use a truss or trusses. For example, thetrusses can be arched or angled ribbons, for example, that help tostabilize the flexible drive shaft.

The eccentric cutting of the devices provided herein can offer safe andclean cutting in tortuous and non-tortuous vessels, as well as eccentriclesions. The lateral pushing member 444 increases safety because,without such lateral protrusion, the cutter assembly is biased to movetowards the outer side of the vessel curvature, which may accidently cutthe vessel wall instead of the targeted plaque at the inner side of thevessel. The lateral pushing member 444 addresses that problem bycorrecting the bias by bulging the trusses 488 towards the outer side ofthe vessel curvature to laterally push the cutter to the opposite sideof the blood vessel to achieve more controlled, effective, and safecutting than conventional cutters. When debulking an eccentric lesion,for example, the adjustable lateral pushing enables the cutter assemblyto target specifically towards the side of the vessel having the greateramount of the stenotic material to achieve eccentric cutting.

In some embodiments, the effective cutting diameter may be approximatelyhalf the diameter of the cutter plus the lateral extent of theprotrusion from central axis of cutter. For example, if the cutter is2.2 mm in diameter, and the protrusion is extended 3.0 mm from cutteraxis, the effective cutting diameter is 4.1 mm. As can be seen, theeccentric cutting leads to a cutting area that is much larger than thediameter of the cutter.

The magnitude of the protrusion (from slightly protruded to maximallyprotruded) is adjustable, in some embodiments. For example, the distancebetween the two ends or collar of the lateral pushing member can beadjusted. That is, the distance between the two ends or collars of thelateral pushing member can be set as desired. In some embodiments, thedistance between the collars is increased to reduce the expansion of thetrusses and, thus, reduce the deflection of the cutter. Likewise, thedistance between the collars can be decreased to increase the expansionof the trusses and, thus increase the deflection of the cutter. One ofskill will appreciate that a dial, knob, button, or other actuator onthe device can provide the user of the device with a measure of thedistance between the collars of the lateral pushing member 444. In someembodiments, an increase in the distance that the drive shaft has movedrelative to the sheath increases the expansion of the trusses 488.Likewise, in some embodiments, a decrease in the distance that the driveshaft has moved relative to the sheath decreases the expansion of thetrusses 488.

In some embodiments, the proximal portion or proximal end of the lateralpushing member 444 will have a fixed contact with the distal portion ordistal end of the sheath, and the distal portion or distal end of thedrive shaft will have a rotatably translational connection with thecutter; with a component proximal to the cutter, the component includinga race and a step to allow for rotation of the cutter despite thepresence of the drive shaft. The race can be referred to as a “bearingsurface” in some embodiments. The component can be, for example, a fixedrace or bearing; and the like, such that the drive shaft freely rotatesat the distal portion or distal end of the laterally pushing memberwhile the laterally pushing member does not rotate.

Interestingly, it was discovered that the relative flexural stiffness ofthe drive shaft 450 as compared to the trusses 488 can also help controlwhich portion of the cutter 430 makes contact with, and cuts, plaque onthe vascular lumen wall 499. For example, if the flexural stiffness ofthe drive shaft 450 is greater than the flexural stiffness of thetrusses 488, then the expansion of the trusses 488 will likely not causea deformation 490 of the drive shaft 450, and the contact between thecutter 430 and the vascular lumen wall 499 will occur moreso on the sideof the body of the cutter 430. However, if the flexural stiffness of thedrive shaft 450 is less than the flexural stiffness of the trusses 488,the drive shaft 450 is expected to deform, and the contact between thecutter 430 and the vascular lumen wall 499 will begin to occur moresotoward the distal end of the cutter 430.

In some embodiments, the flexural stiffness of the distal portion of theflexible atherectomy device, F_(D), is less than or equal to theflexural stiffness of the lateral pushing member, F_(LPM). In someembodiments, the flexural stiffness of the distal portion of theflexible atherectomy device, F_(D), is greater than or equal to theflexural stiffness of the lateral pushing member, F_(LPM). In someembodiments, the flexural stiffness of the distal portion of theflexible atherectomy device, F_(D), is greater than the flexuralstiffness of the lateral pushing member, F_(LPM).

F_(D) can be reduced relative to F_(LPM) by 75%, 70%, 65%, 60%, 55%,50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, or any amount or rangetherein in increments of 1%. In some embodiments, F_(D) can be reducedrelative to F_(LPM) in an amount ranging from about 25% to about 80%,from about 30% to about 75%, from about 35% to about 75%, from about 40%to about 75%, from about 45% to about 75%, from about 50% to about 75%,from about 60% to about 75%, from about 65% to about 75%, from about 70%to about 75%, or any range therein in increments of 1%. Likewise, insome embodiments, F_(D) can be reduced relative to F_(LPM) in an amountranging from about 25% to about 50%, from about 30% to about 50%, fromabout 35% to about 50%, from about 40% to about 50%, from about 45% toabout 50%, or any range therein in increments of 1%. Likewise, in someembodiments, F_(D) can be reduced relative to F_(LPM) in an amountranging from about can be reduced by at least 20%, at least 30%, atleast 40%, at least 50%, at least 60%, at least 70%, at least 80%, atleast 90%, or at least any range or amount therein in increments of at1%.

Given this information, one of skill will appreciate that the amount ofdeformation can be selected by selecting the relative ratios of flexuralstiffness of the drive shaft 450 and the trusses 488, which will allowadditional control of the cutter to the user of the atherectomy device.As such, in some embodiments, the atherectomy device 400 can be designedsuch that the flexural stiffness of the trusses 488 is greater than theflexural stiffness of the drive shaft 450 to obtain a desired amount ofdeflection of the drive shaft to direct a desired surface of the cutter430 to the vascular lumen wall 499. In some embodiments, the flexuralstiffness of the drive shaft can be equal to or greater than theflexural stiffness of the trusses 488 to avoid a deflection of the driveshaft. One of skill will appreciate that there are methods to vary theflexural stiffness of the drive shaft. The stiffness or flexibility ofthe drive shaft may be adjusted, for example, by varying the orientationor association of the filaments that compose the drive shaft. In someembodiments, to increase flexural stiffness, the filaments on the shaftcan be bound together with stiffer material, or the flexural stiffnesscan be increased (or reduced) by increasing (or decreasing) the filamentsize.

The lateral pushing member can be designed to expand to a curvedprotuberance. In some embodiments, the lateral pushing member cancollapse to have an effective radius 445 c that is less than or equal tothe radius of the sheath. In some embodiments, the lateral pushingmember can collapse to have an effective radius 445 c that is less thanor equal to the radius of the cutter. In some embodiments, the lateralpushing member collapses to have an effective radius 445 c that is lessthan or equal to the radius of the cleared diameter of the cutter tohelp facilitate movement of the device in the blood vessel.

Torsional stress on the lateral pushing member 444 is a designconsideration. In order to reduce the concerns about the torsionalstress induced on the lateral pushing member 444, the torsional stresson the distal end of the lateral pushing member can be reduced, thetorsional stiffness of the lateral pushing member can be increased, orboth of these design modifications can be implemented.

FIG. 4C provides an alternate operable connection between the cutter andthe lateral pushing member to address torsional stresses, according tosome embodiments. In some embodiments, the distal race is fixed andserves as a bearing race against the rotating cutter 430. In someembodiments, however, the distal race 477 rotates in contact with arotating cutter 430 and the distal collar 466 of the lateral pushingmember 444. As such, the distal race 477 can be freely rotating, inwhich the distal race 477 freely rotates to further reduce the torsionalstress on the lateral pushing member 444. In some embodiments, thedistal race 477 can be made of a low friction material, such as TEFLON.

FIG. 4D illustrates how a curve can be induced in the distal portion ofthe atherectomy device as deformation 490. As discussed herein, therelative flexural stiffnesses of the distal portion of the drive shaft450 and the lateral pushing member can induce the formation of the curveas force is applied to induce lateral expansion of trusses 488, asdescribed above, also changing the orientation of the cutter 430 in thevessel lumen (not shown). The deformation 490 can be returned to astraight position as shown in FIB. 4B by telescoping the drive shaft 450out from the sheath 415. This re-aligns the cutter 430 in the vessellumen (not shown), from a position where the distal cutter is orientedto cut, to a position where the side of the cutter 430 is oriented tocut.

It should be appreciated that each of the telescoping feature, theself-driving feature, and the lateral pushing feature are distincttechnical advantages. As such, the atherectomy device can be aself-driving atherectomy device only, meaning the device doesn't requiretelescoping or lateral pushing. In these embodiments, the components ofwhich can be labeled the same or similar to the other embodiments taughtherein, the device can have a distal portion with a distal end, aproximal portion with a proximal end, a long axis with a central axis,and a guidewire lumen passing through the device in the direction of thelong axis. The device can include a flexible sheath having an outerdiameter and a sheath lumen; a cutter having a proximal end, a distalend, and a body with a plurality of helical flutes. There can also be apoint at the distal end of the cutter having a plurality of cuttinglips, as well as a cutter lumen, and a cleared diameter. These devicesalso include a drive assembly. The drive assembly can have a flexibledriveshaft including an axis, a proximal end, a distal end, an outersurface, and a driveshaft lumen, the distal end of the flexible driveshaft having a fixed connection with the cutter, wherein the flexibledrive shaft is rotatably translational with the lumen of the flexiblesheath. The drive assembly can also have a screw pump attached to theouter surface of the drive shaft and adjacent to the helical flutes atthe proximal end of the cutter. The screw pump can include a drive screwportion. In some embodiments, the drive screw portion can be the distalportion of the screw pump.

To be self-driving, for example, the drive screw portion can extendbeyond the flexible sheath and can be exposed for contact with avascular lumen during use of the atherectomy device. To effectivelyassist in driving the device through the vascular lumen, the drive screwshould turn in the same direction as the cutter. For example, if theflutes of the cutter spiral in the right hand direction the drive screwshould spiral in the right hand direction. Likewise, if the flutes ofthe cutter spiral in the left hand direction the drive screw shouldspiral in the left hand direction. As such, in some embodiments, thedrive screw portion can be a right hand screw when the cutter is rotatedin the right-hand direction; and, in some embodiments, the drive screwportion can be a left hand screw when the cutter is rotated in theleft-hand direction.

The relative size of the lumen, the cutter, and the drive screw can bedesigned to optimize the self-driving feature. In these embodiments, thecleared diameter of the cutter can be greater than the outer diameter ofthe flexible drive shaft; and, in some embodiments, the cleared diameterof the cutter can be greater than the outer diameter of the flexiblesheath.

Of course, any of the self-driving devices can also include atelescoping feature, the components of which can be labeled the same orsimilar to the other embodiments taught herein. For example, theflexible drive shaft of the self-driving atherectomy device can belonger than the flexible sheath to enable a reversible telescoping ofthe drive assembly from the lumen of the flexible sheath at the distalend of the flexible sheath.

Moreover, any of the self-driving devices can also include areversibly-expandable, lateral pushing member, the components of whichcan be labeled the same or similar to the other embodiments taughtherein. In some embodiments, the lateral pushing member can have aproximal end, a distal end, a collapsed state, and an expanded state,the proximal end having an operable connection with the flexible sheath,and the distal end having an operable connection with the cutter. Theoperable connection with the flexible sheath and the operable connectionwith the cutter can each be configured to receive an axial force (i)applied along the axis of the flexible drive shaft from the cutter tothe flexible sheath and (ii) transferred through the lateral pushingmember during the collapse and the expansion of the lateral pushingmember with the reversible telescoping of the flexible drive shaft fromthe flexible sheath. Moreover, in some embodiments, the operableconnection with the cutter can be configured as a rotatably translatableconnection to facilitate a rotation of the cutter and the flexible driveshaft without rotating the lateral pushing member, particularly thedistal portion of the lateral pushing member, during operation of theatherectomy device.

Likewise, the atherectomy device can be a lateral pushing atherectomydevice only, a device doesn't require self-driving, the components ofwhich can be labeled the same or similar to the other embodiments taughtherein. It does require telescoping, however, at least to the extentneeded for an expanding and a collapsing of the lateral pushing member.In these embodiments, the device can have a distal end, a proximal end,a long axis, and a guidewire lumen passing through the device in thedirection of the long axis. The device can include a flexible sheathhaving an outer diameter and a sheath lumen. The device can have acutter having a proximal end, a distal end, and a body with a pluralityof helical flutes, a point at the distal end having a plurality ofcutting lips, a cutter lumen, and a cleared diameter; and, a driveassembly. The drive assembly can have a flexible driveshaft including anaxis, a proximal end, a distal end, an outer surface, and a driveshaftlumen, the distal end of the flexible drive shaft having a fixedconnection with the cutter, wherein the flexible drive shaft isrotatably translational with the lumen of the flexible sheath. The driveassembly can also have a positive displacement pump that begins pumpingat the distal end of the drive shaft and adjacent to the helical flutesat the proximal end of the cutter. And, the lateral pushing atherectomydevice can also have a reversibly-expandable, lateral pushing member atthe distal end of the flexible sheath.

The relative size of the lumen and the cutter can be designed tooptimize movement of the atherectomy device through the lumen. Forexample, the cleared diameter of the cutter can be greater than theouter diameter of the flexible drive shaft. In some embodiments, thecleared diameter of the cutter can be greater than the outer diameter ofthe flexible sheath. The size of the cutter lumen and the drive shaftlumen can be configured for passage of a guidewire of a desired gaugeand, accordingly, the guidewire lumen can include the cutter lumen andthe driveshaft lumen.

In some embodiments, the lateral pushing member can have a proximalportion with a proximal end, a distal portion with a distal end, acollapsed state, and an expanded state, the proximal end having anoperable connection with the flexible sheath, and the distal end havingan operable connection with the cutter. In some embodiments, theoperable connection with the flexible sheath and the operable connectionwith the cutter can each be configured to receive an axial force (i)applied along the axis of the flexible drive shaft from the cutter tothe flexible sheath and (ii) transferred through the lateral pushingmember during the collapse and the expansion of the lateral pushingmember with the reversible telescoping of the flexible drive shaft fromthe flexible sheath. And, in some embodiments, the operable connectionwith the cutter can be configured as a rotatably translatable connectionto facilitate a rotation of the cutter and the flexible drive shaftwithout rotating the lateral pushing member during operation of theatherectomy device.

In some embodiments, atherectomy device can also be telescoping, thecomponents of which can be labeled the same or similar to the otherembodiments taught herein. That is, the flexible drive shaft of thelaterally pushing atherectomy device can be longer than necessary forthe expansion of the lateral pushing member. The flexible drive shaft ofthe laterally pushing atherectomy device can be longer than flexiblesheath to enable a reversible telescoping of the drive assembly from thelumen of the flexible sheath at the distal end of the flexible sheath.

And, in some embodiments, the lateral pushing atherectomy device canalso be self-driving, the components of which can be labeled the same orsimilar to the other embodiments taught herein. That is, the lateralpushing atherectomy device can comprise a drive screw attached to theouter surface of the distal end of the drive shaft and adjacent to thescrew pump at the distal end of the screw pump. The drive screw can be apart of the screw pump, and it can extend beyond the flexible sheath andbe exposed for contact with a vascular lumen during use. In someembodiments, the drive screw can be a right hand screw when the cutteris rotated in the right-hand direction; and, in some embodiments, thedrive screw can be a left hand screw when the cutter is rotated in theleft-hand direction.

We found that the ratios of (i) dimensions and (ii) stiffness of anatherectomy device taught herein each contribute to the performance andbehavior of the device, the ease of advancement of the cutter, theability to rotate the atherectomy device, the ability to steer thedevice, the relative amount of plaque removed, and the like. Table 2provides example dimensions of the components of the atherectomy device,and Table 3 provides example ratios of the dimensions of the componentsof the atherectomy device.

TABLE 2 Examples of component dimension in mm. Minimum Screw Drive FrontLateral Pump Shaft Sheath Cutting Guidewire Pushing Cutter OD OD OD ODSheath Diameter Lumen ID Member (mm) (mm) (mm) (mm) ID (mm) (mm) (mm) OD(mm) DESIGNED FOR LARGER ARTERIAL DIAMETERS 1.09-3.28 0.64-1.910.43-1.30 0.84-2.51 0.82-2.45 0.32-0.95 0.20-0.61 0.89-2.67 or or or oror or or or 1.64-2.73 0.95-1.59 0.65-1.08 1.26-2.10 1.22-2.04 0.48-0.790.30-0.51 1.34-2.23 DESIGNED FOR SMALLER ARTERIAL DIAMETERS 0.70-2.100.51-1.52 0.43-1.30 0.69-2.06 0.65-1.95 0.32-0.95 0.20-0.61 N/A or or oror or or or 1.05-1.75 0.76-1.27 0.65-1.08 1.03-1.71 0.98-1.63 0.48-0.790.30-0.51

TABLE 3 Examples of ratios of component dimensions Minimum CutterMinimum Front Screw OD: Cutter Front Cutting Pump Cutter OD : Screw OD:Cutting OD: OD: Screw OD: Lateral Pump Sheath Diameter: Guidewire SheathDrive Shaft Pushing OD OD Cutter OD Lumen ID ID OD Member OD DESIGNEDFOR LARGER ARTERIAL DIAMETERS 1.26-3.79 1.00-1.95 0.15-0.44 1.00-2.350.39-1.17 1.00-2.21 1.00-1.84 or or or or or or or 1.90-3.163 0.98-1.630.22-0.36 1.17-1.96 0.58-0.97 1.10-1.84 0.92-1.53 DESIGNED FOR SMALLERARTERIAL DIAMETERS 1.00-2.07 1.00-1.53 0.23-0.68 1.00-2.35 0.39-1.171.00-1.76 N/A or or or or or or 1.03-1.72 1.00-1.28 0.34-0.57 1.17-1.960.59-0.98 1.00-1.47

-   The “Cutter OD” is the largest outer diameter of the cutter.-   The “Screw Pump OD” is the outer diameter of the drive shaft plus    the two diameters of the screw pump wires surrounding the drive    shaft.-   The “Drive Shaft OD” is the outer diameter of the drive shaft and    does not include the two diameters of the screw pump wires.-   The “Sheath ID or OD” is the inner diameter or outer diameter of the    flexible tube, or “sheath”.-   The “minimum front cutting OD” is the outer diameter of the most    distal end of the cutter having cutting edges.-   The “guidewire lumen ID” is the inner diameter of the guidewire    lumen.-   The “lateral pushing member OD” is the outer diameter of the lateral    pushing member and can be taken in the collapsed state or the    expanded state.

It was found that the relative sizes of the device component had asignificant impact on the movement of the device within a vessel lumen.In some embodiments, the cutter diameter should be at least 30% greaterthan the drive shaft diameter. The ratio of cutter diameter to driveshaft diameter can range from 1.3 to 2.0 in some embodiments, 1.3 to 1.8in some embodiments, 1.3 to 1.7 in some embodiments, 1.3 to 1.6 in someembodiments, 1.3 to 1.5 in some embodiments, 1.3 to 1.4 in someembodiments, or any range therein. In some embodiments, the ratio ofcutter diameter to drive shaft diameter can be 1.3, 1.4, 1.5, 1.6, 1.7,1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or 2.5, or any ratio therein inincrements of 0.05, in some embodiments. In some embodiments, however,the cutter diameter is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%,20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%,34%, 35%, 36%, 37%, 38%, 39%, 40%, or any percent therein in incrementsof 0.5%, greater than the drive shaft diameter.

In some embodiments, the cutter diameter should be at least 20% greaterthan the sheath. The ratio of cutter diameter to sheath diameter canrange from 1.2 to 2.0 in some embodiments, 1.2 to 1.8 in someembodiments, 1.2 to 1.7 in some embodiments, 1.2 to 1.6 in someembodiments, 1.2 to 1.5 in some embodiments, 1.2 to 1.4 in someembodiments, 1.2 to 2.0 in some embodiments, or any range therein. Insome embodiments, the ratio of cutter diameter to drive shaft diametercan be 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,or 2.5, or any ratio therein in increments of 0.05, in some embodiments.In some embodiments, however, the cutter diameter is 5%, 6%, 7%, 8%, 9%,10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%,24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%,38%, 39%, 40%, or any percent therein in increments of 0.5%, greaterthan the sheath diameter.

The skilled artisan will appreciate that, given the teachings herein,the drive shaft, sheath and, in some embodiments, the lateral pushingmember can be designed to have mechanical and physical properties thatare desirable for the atherectomy procedure. In some embodiments, themechanical and physical properties of the device provide adequatestrength to push the cutter forward during the procedure yet flexibleenough to maneuver and align the cutter with the guidewire in tortuousvessels.

One of skill will appreciate that the technology provided herein caninclude flexural stiffness design selections for components tofacilitate enhanced performance, maneuverability, and reliability of theatherectomy devices. Flexural stiffness is a measure of deformabilityexpressed in units of N/mm. For example, flexural stiffness may bedescribed as the ability of the component to bend in response to anapplied bending force without breaking or deforming the component. Forexample, one of skill may choose a flexural stiffness of the driveshaft, sheath, or both, in some embodiments, for maneuverability of theatherectomy device to follow a guide wire around tortuous vessels.

One of skill will also appreciate that the technology provided hereincan include torsional stiffness design selections for components tofacilitate enhanced performance through torsional strength. Torsionalstiffness is resistance to twist from torsional loading, allowing thecomponent to transmit a rotational load (torque) without untwisting,over-twisting. and/or deforming, and is in units of N*mm/rad. Forexample, one of skill may choose a torsional stiffness of the driveshaft, lateral pushing member or both, in some embodiments, to helpensure that the cutter can cut against resistance from the plaquewithout failure of the drive shaft, and the lateral pushing memberdoesn't rotate, or at least rotates only a limited amount, to avoidfailure of the lateral pushing member device during the atherectomyprocedure.

One of skill will also appreciate that the technology provided hereincan include axial tensile stiffness design selections for components tofacilitate enhanced performance through better response of theatherectomy devices to push and pull. Axial tensile stiffness is theresistance to stretch or contraction of along the length of thecomponent under axial loading and is in units of N/mm. Key componentsthat should include an axial tensile stiffness design selection includethe drive shaft, the sheath, and the lateral pushing member.

Tables 4 and 5 provide examples of flexural stiffness, torsionalstiffness, and axial stiffness of components of the atherectomy devicestaught herein, as well as ratios of the relative stiffnesses of thecomponents.

TABLE 4 Example component stiffnesses for the atherectomy devices.Lateral Lateral Lateral Drive Drive Drive Pushing Pushing Pushing ShaftShaft Shaft Sheath Member Member Member Flexural Torsional AxialFlexural Torsional Axial Flexural Stiffness Stiffness StiffnessStiffness Stiffness Stiffness Stiffness (N/mm) (N*mm/rad) (N/mm) (N/mm)(N*mm/rad) (N/mm) (N/mm) 0.09-0.6 12.73-38.20 2.59-7.76 0.72-2.150.75-2.24 0.82-2.45 0.40-1.20 or or or or or or or 0.13-0.22 19.10-31.833.88-6.46- 1.07-1.79 1.12-1.86 1.23-2.04 0.60-1.00

TABLE 5 Examples of ratios of the relative component stiffnesses for theatherectomy devices. Lateral Pushing Drive Drive Drive Drive MemberShaft Shaft Sheath Shaft Shaft Torsional Axial Flexural Flexural DriveShaft Drive Shaft Flexural Torsional Stiffness: Stiffness: Stiffness:Stiffness: Flexural Flexural Stiffness: Stiffness: Lateral LateralLateral Lateral Stiffness: Stiffness: Drive Drive Pushing PushingPushing Pushing Sheath Drive Shaft Shaft Shaft Member Member MemberMember Flexural Torsional Axial Axial Axial Axial Flexural FlexuralStiffness Stiffness Stiffness Stiffness Stiffness Stiffness StiffnessStiffness 0.06-0.18 0.003-0.010 0.02-0.05 2.46-7.39 0.46-1.37 1.58-4.740.11-0.33 0.89-2.67 or or or or or or or or 0.09-0.15 0.005-0.0090.03-0.04 3.69-6.16 0.68-1.14 2.37-3.95 0.16-0.27 1.34-2.23

The flexural stiffness of the sheath should be at least 3× greater thanthe drive shaft, in some embodiments. The ratio of flexural stiffness ofthe drive shaft to the flexural stiffness of the sheath can range from0.03 to 0.40 in some embodiments, 0.05 to 0.30 in some embodiments, 0.05to 0.25 in some embodiments, 0.06 to 0.30 in some embodiments, or anyrange therein. In some embodiments, the ratio of flexural stiffness ofthe drive shaft to the flexural stiffness of the sheath can be 0.03,0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15,0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27,0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39,0.40 or any ratio or range therein in increments of 0.005, in someembodiments. In some embodiments, however, the flexural stiffness of thesheath is 3×, 4×, 5×, 6×, 7×, 8×, 9×, 10×, or any range therein, greaterthan the flexural stiffness of the drive shaft.

FIGS. 5A-5C illustrate a compressible sleeve that can be used toincrease the torsional stiffness of the lateral pushing member, create ashield for the positive displacement pump, and increased the pumpingefficiency to improve movement of cut particles out of the vessel,according to some embodiments. FIGS. 5A and 5B show that thecompressible sleeve 500 has a proximal portion 505, a distal portion510, and a compressible portion 515 having a spiral wound band thatincludes a gap between each of the spirals, a pitch between each of thespirals and a width and thickness of the spiral wound band. In someembodiments, the spiral wound band of the compressible portion 515 isintegral with the proximal portion 505 and the distal portion 505.

FIG. 5C illustrates a deformation 590 of the distal portion of theatherectomy device. As discussed herein, the relative flexuralstiffnesses of the distal portion of the drive shaft 550 and the trusses588 in the lateral pushing member can induce the formation of the curve590 as force is applied to induce lateral expansion of trusses 588, asdescribed above, also changing the orientation of the cutter 630 in thevessel lumen (not shown). The compressible sleeve 500 compresses thespiral wound band of the compressible portion 515 during the lateralexpansion of the trusses 588 and the creation of the deformation 590 ofthe drive shaft and compressible sleeve 500. As such, the expansion ofthe trusses 588 in the lateral pushing member can induce a curve 590 onthe distal portion of the atherectomy device, according to someembodiments.

FIG. 5D illustrates a release of the deformation 590 of the distalportion of the atherectomy device to straighten the distal portion ofthe atherectomy device. The drive shaft 550 is telescoped out of thesheath (not shown) to relax the forces between the drive shaft 550 andtrusses 588 and straighten the drive shaft 550 and trusses 588. Thisre-aligns the cutter 530 in the vessel lumen (not shown), from aposition where the distal portion of the cutter 530 is oriented to cut,to a position where the side of the cutter 530 is oriented to cut. Thecompressible sleeve 500 relaxes and returns the spiral wound band of thecompressible portion 515 from the deformation 590 caused by the lateralexpansion of the trusses 588 to the original straight position as shownin FIG. 5D. As such, the expansion of the trusses 588 in the lateralpushing member can release deformation 590 on the distal portion of theatherectomy device and return to a straight position, according to someembodiments.

The compressible sleeve 500 can be placed outside of the flexible driveshaft and in-between the proximal and distal ends of the lateral pushingmember, such that the flexible drive shaft 550 spins inside of thecompressible sleeve. As shown herein, there can be a collar at each endof the laterally pushing member, a proximal collar and a distal collar,and the proximal portion 505 of the compressible sleeve 500 is operablyattached to the proximal collar of the lateral pushing member, and thedistal portion 510 of the compressible sleeve 500 is operably attachedto the distal collar of the lateral pushing member. Due to the design ofthe compressible portion 515, the compressible sleeve 500 may be bentand compressed when the ribbons of the lateral pushing member protrudeoutwardly from a flat state while providing an added torsional stiffnessbetween the proximal collar and the distal collar of the lateral pushingmember to address torsion stresses on the lateral pushing member. Insome embodiments, the distal and proximal collars of the lateral pushingmember do not twist relative to each other, or any torsional movement isat least reduced. The compressible sleeve 500 also serves to cover thepositive displacement pump, referred to as an Archimedes screw in someembodiments. As such, the compressible sleeve 500 can act as a safetyshield during aspiration of the cut plaque particles with the Archimedesscrew. And, it should be appreciated that having the cover over thepositive displacement pump mechanism can assist the pump in the removalof particles by helping to retain the particles in a fixed space. Forexample, in the case of the screw pump, the compressible sleeve is inclose proximity to the screw mechanism to retain plaque particles in thelumen of the compressible sleeve 500, helping the screw mechanism 580move the particles out of the treated blood vessel with more efficiency.Moreover, the expanded trusses 588 of the lateral pushing member requirethe proximal and distal collars of the lateral pushing member to movecloser together when compressing the compressible sleeve 500, thecompressing occurring in the gaps between the spirals of thecompressible sleeve 500 to allow the shortening to occur.

The compressible sleeve 500 can be made of any suitable material knownto one of skill, the choice of material dictating the required bandwidth and thickness, for example. In some embodiments, the compressiblesleeve may be made of stainless steel, Nitinol, other metal alloys, orpolymers, PEEK, polycarbonate, nylon, or polyimide.

Example dimensions for the compressible sleeve 500 are listed in Table6, at least for lower extremity vasculature,

TABLE 6 Dimensions of the compressible sleeve designed for use invasculature″ Outer Diameter Inner Diameter OD (mm) ID (mm) Pitch (mm)Gap (mm) 0.76-2.29 0.70-2.10 0.38-1.14 0.13-0.38 or or or or 1.14-1.911.05-1.75 0.57-0.95 0.19-0.32

TABLE 7 Flexural and torsional stiffness of the drive shaft andcompressible sleeve. Drive Shaft Compressible Sleeve Flexural TorsionalAxial Flexural Torsional Axail Stiffness Stiffness Stiffness StiffnessStiffness Stiffness (N/mm) (N-mm/rad) (N/mm) (N/mm) (N-mm/rad) (N/mm)0.09-0.26 12.73-38.20 2.59-776 0.03-0.08 0.02-0.05 0.04-0.12 or or or oror or 0.13-0.22 19.10-31.83 3.88-6.46 0.04-0.06 0.03-0.04 0.06-0.10

The stiffness and ratio of the drive shaft and the compressible sleeveare listed below in Tables 8 and 9:

TABLE 9 Ratio of the stiffness of the drive shaft and the compressiblesleeve for vasculature Drive Shaft Drive Shaft Flexural Stiffness: AxialStiffness: Sleeve Compressible Sleeve Compressible Axial StiffnessFlexural Stiffness >32.97 1.71-5.13 or or >49.46 2.56-4.27

The flexural stiffness of the drive shaft should be at least 50% greaterthan the drive compressible sleeve, in some embodiments. The ratio offlexural stiffness of the drive shaft to the flexural stiffness of thecompressible sleeve can range from 1.5 to 6.0 in some embodiments, 1.5to 5.0 in some embodiments, 1.6 to 5.0 in some embodiments, 1.7 to 5.0in some embodiments, or any range therein. In some embodiments, theratio of flexural stiffness of the drive shaft to the flexural stiffnessof the compressible sleeve can be 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.2,2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0,5.2, 5.4, 5.6, 5.8, 6.0, or any ratio or range therein in increments of0.1, in some embodiments. In some embodiments, however, the flexuralstiffness of the drive shaft is 2×, 3×, 4×, 5×, 6×, or any amount inincrements of 0.1×, or any range therein, greater than the flexuralstiffness of the compressible sleeve.

Although the performance of cutters can vary, depending on factors thatinclude tissue type, for example, any cutter known to one of skill maybe used with the atherectomy devices taught herein. FIGS. 6A and 6Billustrate other cutters that may be used, according to someembodiments. FIGS. 6A and 6B both show a cutter 600 having a distal end601, proximal end 603, lumen 605, and flutes 607. The cutter 600 of FIG.6A also has a burr portion 609, and the cutter 600 of FIG. 6B has ahammer portion 611.

The cutter in FIG. 6A has a burr portion 609 which can be fixed on thecutter, in some embodiments. In some embodiments, the burr portion 609can be formed monolithically integral to the cutter. In someembodiments, however, the burr portion 609 can be operably attached tothe cutter using a friction fitting, so that the burr is allowed slip onthe base of the cutter when engaged with plaque and meeting a maximumtorque limit.

The cutter in FIG. 6B has hammer portion 611 which can be fixed on thedrive shaft, in some embodiments. In some embodiments, the hammerportion 611 can be operably attached to the cutter using a frictionfitting, so that the hammer portion is allowed slip on the drive shaftwhen engaged with plaque and meeting a maximum torque limit. The hammerportion 611 has oscillating teeth 613 that contact the blade portion 612to create an oscillating hammer effect on the plaque for cutting.

Atherectomy systems can also be assembled to include the atherectomydevices taught herein. In some embodiments, any of the atherectomydevices taught herein can be a system comprising the atherectomy deviceand a guidewire.

The atherectomy devices also lend to several methods of performing anatherectomy in a subject. In some embodiments, the methods can includecreating a point of entry in a vascular lumen of the subject; insertingthe atherectomy device into the vascular lumen; telescoping the flexibledrive shaft; cutting a plaque from the vascular lumen with the cutter ofthe atherectomy device; discharging the cut plaque from the vascularlumen with the positive displacement pump; and, removing the atherectomydevice from the vascular lumen of the subject.

In some embodiments, the methods can include creating a point of entryin a vascular lumen of the subject; inserting the atherectomy deviceinto the vascular lumen; driving the atherectomy device through thevascular lumen with the exposed drive screw; cutting a plaque from thevascular lumen with the cutter of the atherectomy device; dischargingthe cut plaque from the vascular lumen with the positive displacementpump; and, removing the atherectomy device from the vascular lumen ofthe subject.

Likewise, in some embodiments, the methods can include creating a pointof entry in a vascular lumen of the subject; inserting the atherectomydevice into the vascular lumen; pushing the distal portion of theatherectomy device laterally in the vascular lumen, the pushingincluding expanding the lateral pushing member; cutting a plaque fromthe vascular lumen with the cutter of the atherectomy device;discharging the cut plaque from the vascular lumen with the positivedisplacement pump; and, removing the atherectomy device from thevascular lumen of the subject.

Likewise, in some embodiments, the methods can include grinding theplaque with a burr like, for example, the burr portion 609 of FIG. 6A.The burr can having ridges, like the burr portion 609, or it can be agrinding surface having a desired “grit”.

Likewise, in some embodiments, the methods can include hammering theplaque with a hammering cutting blade configuration like, for example,the cutting portion 612 of the cutter of FIG. 6B.

One of skill will appreciate that the steps set-forth above representonly example of a series of steps that may be used in an atherectomy. Ina simple embodiment, for example, the method includes

-   inserting an atherectomy device taught herein into a vascular lumen    of a subject, the atherectomy device having a distal end, a proximal    end, a long axis, and a guidewire lumen passing through the device    in the direction of the long axis;-   a flexible sheath having an outer diameter and a sheath lumen; a    cutter having a proximal end, a distal end, and a body with a    plurality of helical flutes, a point at the distal end having a    plurality of cutting lips, a cutter lumen, and a cleared diameter;    and,-   a drive assembly having    -   a flexible driveshaft including an axis, a proximal end, a        distal end, an outer surface, and a driveshaft lumen, the distal        end of the flexible drive shaft having a fixed connection with        the cutter, wherein the flexible drive shaft is rotatably        translational with the lumen of the flexible sheath; and,    -   a positive displacement pump that begins pumping at the distal        end of the drive shaft and adjacent to the helical flutes at the        proximal end of the cutter;    -   advancing the cutter to a target area in the vascular lumen of        the subject, the advancing including-   telescoping the distal end of the flexible drive shaft away from the    distal end of the flexible sheath to increase the flexibility of the    atherectomy device in the vascular lumen; self-driving the cutter    into the target region, the self-driving including turning a screw    at the distal end of the flexible drive shaft;-   laterally pushing the distal end of the flexible sheath, distal end    of the flexible drive shaft, and the cutter against the wall of the    vascular lumen; or,-   a combination thereof;    -   cutting plaque away from the wall of the vascular lumen, the        cutting including rotating the cutter; and,    -   removing the plaque from the vascular lumen using the positive        displacement pump; and,    -   removing the atherectomy device from the subject.

It should be appreciated that the devices, systems and methods providedherein allow for enhanced functionality during an atherectomy procedure.In some embodiments, a method of steering a cutting head are provided,and these methods can include redirecting the distal end of the flexibleatherectomy device. In some embodiments, the redirecting can include

-   (i) expanding the pushing member, the expanding including pulling a    centralized “member”-   (ii) wherein the expanding expands the lateral pushing member to    push and bend/curve the distal end of the flexible atherectomy    device.

The centralized “member” can be, for example, either the flexible driveshaft, or perhaps a centralized tendon that is also freely translatablein the axial direction, meaning translatable in the longitudinal axisdirection, and perhaps even forming the guidewire lumen in someembodiments. A truly surprising and unexpected benefit was provided bythe centralized pull on or near the central axis of the atherectomydevice, central axis of the sheath, and or central axis of the driveshaft. To reiterate this surprising result, prior art Telescoping,self-driving, and laterally-pushing atherectomy devices are provided,each having a flexible sheath, a cutter with helical flutes, and a driveassembly. The drive assembly can have a flexible driveshaft that isrotatably translational with the lumen of the flexible sheath, apositive displacement pump that begins pumping at the distal end of thedrive shaft adjacent to the helical flutes at the proximal end of thecutter, and the flexible drive shaft can be longer than the flexiblesheath to enable a reversible telescoping of the drive assembly from thelumen of the flexible sheath. The positive displacement pump can be ascrew pump having a drive screw portion extending beyond the flexiblesheath, exposed for contact with a vascular lumen for the self-driving.And, the devices can have a reversibly-expandable, lateral pushingmember at the distal end of the flexible sheath for the lateral pushing.

We claim:
 1. An atherectomy device, comprising: a distal end, a proximalend, a long axis, and a guidewire lumen passing through the device inthe direction of the long axis; a flexible sheath having an outerdiameter and a sheath lumen; a cutter having a proximal end, a distalend, and a body with a plurality of helical flutes, a point at thedistal end having a plurality of cutting lips, a cutter lumen, and acleared diameter; and, a drive assembly having a flexible driveshaftincluding an axis, a proximal end, a distal end, an outer surface, and adriveshaft lumen, the distal end of the flexible drive shaft having afixed connection with the cutter, wherein the flexible drive shaft isrotatably translational with the lumen of the flexible sheath; apositive displacement pump that begins pumping at the distal end of thedrive shaft and adjacent to the helical flutes at the proximal end ofthe cutter; wherein, the cleared diameter of the cutter is greater thanthe outer diameter of the flexible drive shaft; the flexible drive shaftis longer than the flexible sheath to enable a reversible telescoping ofthe drive assembly from the lumen of the flexible sheath at the distalend of the flexible sheath; and, the guidewire lumen includes the cutterlumen and the driveshaft lumen.
 2. The atherectomy device of claim 1,wherein the cleared diameter of the cutter is greater than the outerdiameter of the flexible sheath.
 3. The atherectomy device of claim 1,wherein the positive displacement pump is a screw pump attached to theouter surface of the drive shaft, the distal end of the screw pump beingadjacent to the helical flutes at the proximal end of the cutter.
 4. Theatherectomy device of claim 3; wherein, the screw pump extends beyondthe flexible sheath and is exposed for contact with a vascular lumenduring use of the atherectomy device within the vascular lumen; is aright hand screw when the cutter is rotated in the right-hand direction;or, is a left hand screw when the cutter is rotated in the left-handdirection;
 5. The atherectomy device of claim 1, further comprising areversibly-expandable, lateral pushing member at the distal end of theflexible sheath.
 6. The atherectomy device of claim 1, furthercomprising a reversibly-expandable, lateral pushing member at the distalend of the flexible sheath, the lateral pushing member having a proximalend, a distal end, a collapsed state, and an expanded state, theproximal end having an operable connection with the flexible sheath, andthe distal end having an operable connection with the cutter; wherein,the operable connection with the flexible sheath and the operableconnection with the cutter are each configured to receive an axial force(i) applied along the axis of the flexible drive shaft from the cutterto the flexible sheath and (ii) transferred through the lateral pushingmember during the collapse and the expansion of the lateral pushingmember with the reversible telescoping of the flexible drive shaft fromthe flexible sheath; and, the operable connection with the cutter isconfigured as a rotatably translatable connection to facilitate arotation of the cutter and the flexible drive shaft without rotating thelateral pushing member during operation of the atherectomy device.
 7. Asystem comprising the atherectomy device of claim 1 and a guidewire. 8.A method of performing an atherectomy in a subject using the atherectomydevice of claim 1, the method comprising creating a point of entry in avascular lumen of the subject; inserting the atherectomy device into thevascular lumen; telescoping the flexible drive shaft; cutting a plaquefrom the vascular lumen with the cutter of the atherectomy device;discharging the cut plaque from the vascular lumen with the positivedisplacement pump; and, removing the atherectomy device from thevascular lumen of the subject.
 9. A method of performing an atherectomyin a subject using the atherectomy device of claim 4, the methodcomprising creating a point of entry in a vascular lumen of the subject;inserting the atherectomy device into the vascular lumen; telescopingthe flexible drive shaft; cutting a plaque from the vascular lumen withthe cutter of the atherectomy device; discharging the cut plaque fromthe vascular lumen with the positive displacement pump; and, removingthe atherectomy device from the vascular lumen of the subject.
 10. Amethod of performing an atherectomy in a subject using the atherectomydevice of claim 6, the method comprising creating a point of entry in avascular lumen of the subject; inserting the atherectomy device into thevascular lumen; telescoping the flexible drive shaft; cutting a plaquefrom the vascular lumen with the cutter of the atherectomy device;discharging the cut plaque from the vascular lumen with the positivedisplacement pump; and, removing the atherectomy device from thevascular lumen of the subject.